If lactose is accumulating outside of E.coli and is unable to enter,then which structural gene of the lac operon is most likely mutated?
A)lacY
B)lacX
C)lacZ
D)lacI
E)lacA

Question

Quizplus · Accepted Answer

The structural gene lacY codes for the lactose permease, which is responsible for transporting lactose across the bacterial cell membrane. If this gene is mutated, lactose cannot enter the cell and will accumulate outside. The other structural genes lacZ and lacA code for the beta-galactosidase and transacetylase enzymes respectively, which are not involved in lactose transport. The lacX gene does not exist in the lac operon. The lacI gene codes for the lac repressor protein, which regulates expression of the lac operon but is not directly involved in lactose transport.

If Lactose Is Accumulating Outside of E